Re: [PATCH 0/2] x86/cpu: P-state support for Lightning Mountain

[Martin Schiller <ms@dev.tdt.de>]

On 2026-03-09 16:57, srinivas pandruvada wrote:
> On Mon, 2026-03-09 at 07:53 +0100, Martin Schiller wrote:
>> On 2026-03-06 18:59, Rafael J. Wysocki wrote:
>> > On Fri, Mar 6, 2026 at 9:27 AM Martin Schiller <ms@dev.tdt.de>
>> > wrote:
>> > >
>> > > This patch set contains 2 commits to get P-state support for
>> > > Intel /
>> > > MaxLinear Lightning Mountain. The first adds the needed code to
>> > > the
>> > > intel_pstate driver. The second adds a workaround to the x86/cpu
>> > > subsystem to enable EIST on all cpus.
>> >
>> > Can you please combine the patches?
>> >
>> > Or does the first one work just fine without the second one?
>> 
>> Well, the first patch can basically be applied without the second
>> one,
>> but then frequency stepping will only work on the first cpu core.
>> 
>> I split the two changes because they apply to different parts of the
>> kernel sources.
>> 
>> But you're probably right, and it makes sense to combine the two
>> patches.
>> 
>> 
>> BTW: The original code from the MaxLinear SDK enables EIST in the
>> intel_pstate driver, but I don't think that's the right place for it.
> 
> This is a special case. But intel_pstate driver can be disabled from
> kernel command line to use acpi cpufreq driver. So in that case
> enabling in intel_pstate will not help.

You're basically right, but the MaxLinear Lightning Mountain doesn't
support ACPI either, so the acpi cpufreq driver wouldn't work anyway.

So perhaps it would be best after all if I integrated this routine
into the intel_pstate driver.

Regards,
Martin